Article from BMH
for 20 March, 2006
Brattleboro Reformer

Anterior Cruciate Ligament Surgery
By William Vranos, MD

Last month I discussed some emerging therapies which will hopefully lead to prevention of injuries to the anterior cruciate ligament. Unfortunately, injuries to the ACL occur over 100,000 times annually in this country at enormous cost to the patient and health care system. If time lost at work is included with these costs, the total cost to society of this injury is over one billion dollars annually. This article will discuss the rationale for surgical treatment as well as current surgical and rehabilitation techniques used in treating this injury.

Most patients coming to our office with an ACL tear will have surgical reconstruction as their recommended treatment. Almost 50% of patients with an ACL tear will have an associated tear of a meniscal cartilage. Most will have substantial swelling for a week or two. Initially some physical therapy to maintain strength and range of motion will be prescribed. Unfortunately, without surgery, most patients will have instability of the knee with a feeling of “giving way.” Each of these “giving way” episodes risks further cartilage damage. Thus, the natural history of an ACL-deficient knee which is not reconstructed is a gradual loss of cartilage, frequent physician visits and, over many years, arthritis. Bracing may help a little but most patients who elect non-surgical treatment cannot return to high levels of sporting activities and adopt a sedentary lifestyle. Surgical reconstruction eliminates these issues for most patients, allowing them to have a more stable knee and to return to pre-injury activity levels. The timing of surgical treatment is usually elective and the only time that surgery needs to be done urgently is if there is a major cartilage injury which needs attention. Otherwise, the surgery is typically done after a period of rehabilitation from the initial injury, when the patient has restored full range of motion and muscle tone.

The anterior cruciate ligament has no ability to heal itself and early surgical techniques aimed at repairing the torn ligament were not successful. Currently, there is research aimed at using stem cells with ligament healing potential to change this outcome, and primary repair of the ligament may be possible in the future. For now, the most successful techniques involve arthroscopically placing a graft through small tunnels drilled through the bone around the knee. The graft is placed in a position that anatomically recreates the course of the ACL and, as it heals, will recreate normal knee function. Historically, a portion of the patellar tendon was used, but now hamstring tendon or allograft (cadaver) tendons are more commonly placed. Because the procedure is done arthroscopically, incisions are small and most patients go home the day of surgery.

Current post-operative rehabilitation techniques are very aggressive compared with historical methods. The days of casting and prolonged crutch use are over. Patients are given strengthening exercise to begin the night of surgery. Weight bearing is allowed and most patients are off crutches within one to two weeks. A light exercise program is begun within one week of surgery and is progressed as tolerated by the patient. Most can ride an exercise bike within two weeks and begin elliptical training in three. Knee swelling is a problem the first month but usually resolves within six weeks and the program is progressed further at that point, as nautilus use and a light jogging program can begin when the swelling permits. Agility drills are added at this time as well. While some young people can return to sports at four months, six to nine months is more typical, especially in the over 30 population.

Thus, modern surgical and rehabilitation techniques generally lead to good to excellent outcomes in approximately 90% of the patients who have an ACL reconstruction. Major complications are rare but a few grafts will fail in the first year and the re-operation rate in the first year is about 5%. The greatest reason for a sub-optimal outcome is pre-existing knee conditions or significant cartilage injuries or injuries to the other knee ligaments at the time of the ACL tear. Some of these problems are not repairable with current techniques. These instances are rare, however, and most patients can expect consistent post-operative progress and a return to an active lifestyle.